Motor vehicle seat

ABSTRACT

A seat construction for a motor vehicle in which the seat occupant is strapped to the back rest by a safety belt which is secured to the seat rather than to the vehicle body and in which energy-absorbing or dissipating means are provided for consuming a considerable amount of the energy which is produced by the forward propulsion of the seat occupant, for example, in a headon collision, so that the pressure which is then exerted by the safety strap upon the body of the seat occupant will not exceed the bearable limit and this person will thus not be injured at least by the safety belt.

United States Patent [151 3,697,128

Strien et al. [451 Oct. 10, 1972 154] MOTOR VEHICLE SEAT 3,091,4965/1963 Bentley ..297/386 Inventors: Werner sm stungan fleumaden; Splelman Eberhard Faust, stungamoegep 3,081,059 3/1963 Hastings ..297/216loch both of Germany 3,188,133 6/1965 Tewksbury ..297/380 X 3,224,80812/1965 Spielman ..297/378 X [73] Assrgnee: Recaro Aktiengesellschalt,Glarus, 3,424,492 l/ 1969 Tabor ..297/379 Switzerland FOREIGN PATENTS ORAPPLICATIONS [22] Filed: Dec. 3, 1969 l,039,131 8/1966 Great Britain..297/216 [21] Appl. No.: 881,687

Primary Examiner-Francis K. Zugel 3 Foreign Appucauon Priority DataAttorney-Arthur O. Klein Dec. 5, 1968 Germany ..P 18 12 785.0 57ABSTRACT Jan, 31, 1969 Germany..........P 19 04 687.8

A seat construction for a motor vehicle 1n which the 52 U. L seatoccupant is strapped to the back rest by a safety 51} .3 8.iiii'f1337f3ifi1633 heh whhh h hhhheh he he shah hhhhh hhhh h hhh 531Field of Search ..297/216 386 389 378 379 vehicle and ene'gy'absmblngsipatlng means are provided for consuming a considerable amount of theenergy which is produced by the forward propulsion of the seat occupant,for exam- [Sfil References Cited ple, in a headon collision, so that thepressure which is UNITED STATES PATENTS then exerted by the safety strapupon the body of the seat occupant will not exceed the bearable limitand 2,682,93] 7,1954 Young ..297/216X n t d t] th "1 2,966,200 l2/l960Fredhold ..297/216 Q3531? thus be mime a y 6 2,971,566 2/196] Negroni..297/216 2,933,127 4/1960 Brewster ..297/2l6 7Claims,l5 Drawing Figures/5 a /b 5 #25 k9 144 /5-. E 4 70 IE 1 9 i l r PAIENTEDncr 10 m2 3 697'128 SHEET 1 0F 4 Inventors: WERNER STRI EN mo Ebemnao FR ST ATToRNEiPATENTED BT W972 3.697.128

sum 2 0r 4 Inventonn WERNER arm Eeeaunw FA ST ATTORNEY PATENTEU 10 I9723.697.128 saw u or 4 Inventors: WERNER STREINMD EBERHHRD FAUST BwVMmQQAATTDRNEV MOTOR VEHICLE SEAT The present invention relates to a seat fora vehicle, and especially a motor vehicle, upon which the seat occupantis adapted to be strapped by one or more safety belts.

in all automobiles and other motor vehicles which were provided withsafety belts prior to this invention, these belts were secured to partsof the vehicle body. If such a vehicle is suddenly and stronglydecelerated, for example, by a head-on collision, the safety belt alonemust prevent the seat occupant from being propelled forwardly. This maylead to such a severe pressure by the safety belt upon the body of theseat occupant that the latter may suffer serious injuries. Furthermore,since the safety belt leaves the load of such a person unguarded, thehead may be propelled forwardly so severely that the cervical vertebraeof this person may be dangerously bent or even injured seriously.

It is an object of the present invention to provide a seat structure fora motor vehicle which, although it may be of a low cost, considerablyreduces or even entirely eliminates the danger to which the seatoccupant may be subjected due to the fact that in an accident he isstrapped to the seat by a safety belt.

For attaining this object, the present inventors proceeded from theconcept that it would be possible to reduce the load which a safety beltmight exert upon the body of the seat occupant by permitting the latterat a sudden strong deceleration of the vehicle to move for a certaindistance relative to the vehicle and by at least partly absorbing thekinetic energy of the body of the seat occupant by an energy-absorbingor dissipating device. It is therefore the principal feature of thepresent invention to attain the above-mentioned object by providingsuitable means which connect at least the back rest of the seat, towhich at least one of the securing means of the safety belt is secured,to a solid seatsupporting base or floor and which comprise at least onestructural element which, when the load upon the safety belt and by thelatter upon the body of the seat occupant reaches a predetermined limit,hereafter also called the bearable limit, permits at least the back restof the seat together with the seat occupant to move forwardly for acertain distance, and which during this movement absorbs or dissipatesat least some of the energy which is produced by this movement of theseat and the body ofits occupant.

Since at least one of the securing means of the safety belt is securedto the back rest, the forces which are produced by the forwardpropulsion of the body of the seat occupant when a strong decelerationof the vehicle occurs are transmitted by the safety belt to the backrest and thereby tend to pull the backrest forwardly. Theenergy-dissipating connecting element which is adapted to take up theseforces which are exerted upon the back rest therefore only needs to bedesigned so as to permit a forward movement of the back rest not untilthe pressure which the safety belt exerts upon the body of the seatoccupant reaches the limit which such a pcrson can still bear withoutinjury. The energy dissipating connecting element is preferably furtherdesigned so as to maintain this value during the entire movement of theback rest so that during the relatively short distance which is usuallyavailable for this movement the largest possible part of the kineticenergy of the body of the seat occupant will be taken up and dissipatedby the connecting element.

For reasons of design and manufacture as well as for the reason of alack of sufficient space it is advisable to combine theenergy-dissipating element with the actual seat part of the seat so thatthe back rest will only be indirectly supported through the seat partrelative to the solid seat-supporting base. If, for example, due to ahead-on collision of the vehicle the stresses which are exerted by thesafety belt upon the body of the seat occupant exceed the bearablelimit, only the back rest will then move forwardly while the seat partremains immovable relative to its solid support. The seat structure maythen be designed so that this movement of the back rest may be either apivoting movement, a translatory movement or a combination of a pivotingmovement and a translatory movement. However, since it is merelynecessary to permit the body of the seat occupant to move forwardlyrelative to the vehicle when the deceleration of the vehicle exceeds thebearable limit, the same purpose may also be attained if not only theback rest but the entire seat may carry out a pivoting movement, whileat the same time a material part of the energy will be dissipated whichis produced by the deceleration or impact of the vehicle and theresulting movement of the seat occupant. By numerous experiments andpractical tests it has been found that seat constructions of thelast-mentioned type have the advantage that in the event of a seriouscollision of a vehicle the upper part of the body of the seat occupantwill not be pivoted toward his legs. According to a preferred embodimentof the invention, this may be at' tained by providing at least the frontend of the seat part with supporting legs or brackets which arepivotably connected to this seat part as well as to the solid supportingbase or floor.

These supporting legs permit the entire seat to move relative to thesolid floor, which has the result that in the event of a collision theseat occupant will be firmly held on his seat without danger that theload which the safety belt will then exert upon his body will cause anyinjuries.

The means for supporting the seat part near its rear end relative to thebase or floor may be of various designs. Thus, for example, these meansmay likewise consist of supporting legs which are pivotably connected tothe seat part and to the floor so that the front and rear supportinglegs together with the seat part and the floor form an adjustableparallelogram. The energydissipating connecting element is thenpreferably mounted so as to extend diagonally through thisparallelogram. According to another feature of the invention, thisdiagonal connecting element may also be provided with a device formanually adjusting its total length with the result that the shape ofthe parallelogram will be altered and the height of the seat from thefloor will be varied. This adjusting advice may be combined with theenergy-dissipating element so as to form a structural unit.

According to another embodiment of the invention, the seat part isprovided near its rear end with supporting legs which are rigidlysecured thereto and the lower ends of which are slidable in guide meanswhich extend substantially in the longitudinal direction of the seat andare secured to the floor. In order to pivot the seat as much as possibleforwardly and downwardly during its forward movement against the actionof the energydissipating element, it is advisable to incline the guidemeans upwardly toward their front end since this causes the seat to tiltover forwardly and downwardly. The energy dissipating element may thenconnect the lower end of one or both rear legs to a position at the baseor floor, for example, to the pivot axis of the front legs, from whichthe distance to the end of the rear legs decreases when the seat movesforwardly when the stresses reach approximately the bearable limit.

According to another embodiment of the invention, one end of theenergy-dissipating element is pivotably connected to the floor, forexample, at the pivoting point of the front legs, while its other end isslidable along guide means which extend from the seat part obliquelydownwardly and toward the rear. In this embodiment a locking device isprovided for locking the slidable end of the energy-dissipating elementin a fixed position when the seat is located in its normal sittingposition. This embodiment of the invention is especially of advantagefor being employed in a two-door sedan or similar motor vehicle since byreleasing the locking device, for example, by hand, the seat may beshifted forwardly and tilted downwardly since the slidable end of theenergy-dissipating device will slide toward the rear end of the guidemeans. This pennits a passenger to enter easily behind this seat so asto sit down in a rear seat. When the locking device is in the positionin which it locks the slidable end of the energydissipating element in afixed position, the seat may slide forwardly and tilt downwardly only ata sudden strong deceleration of the vehicle against the action of theenergy-dissipating element. It is of advantage that the seat will thenbe pivoted about a relative large angle since the space available for aforward movement of the seat is relatively small. It is also possible inthis seat construction to combine the energy-dissipating element with adevice for adjusting its effective normal length for the purpose ofvarying the height of the seat from the floor since by such a lengthadjustment the front legs of the seat will be pivoted to a differentangle.

At the occurrence of a very strong deceleration of the vehicle it isalso possible to hold the seat occupant by means of the safety belt onhis seat without being injured by the belt ifthe forward movement of theseat be employed for pivoting the seat toward the rear so that the frontedge of the seat part will move upwardly and its rear edge movedownwardly and at the same time forwardly. Such a pivoting movement ofthe seat will place the seat occupant, for example, at a strong impactof the vehicle, into a more or less reclining position with the resultthat by his inertia he will be pressed more firmly against the seatpart.

Such a movement of the seat may according to another feature of theinvention be attained by inclining the longitudinal guide means for therear legs of the seat from their rear ends at least for a certain partof their length in the downward direction and by pivotably connectingthe front legs in such a manner to the seat part and to the floor that,when the seat is in its normal sitting position, these front legs areinclined upwardly and toward the rear. If, for example, in an accident,the seat tends to be propelled forwardly, the front legs will pivotupwardly and lift the front end of the seat part,

while the rear end of the seat part will move downwardly and forwardlyand the back rest will thereby tilt toward the rear.

The energy-dissipating element is preferably provided in this case inthe form of a locking device which releases the seat when the front legsof the latter are pivoted forwardly and upwardly about a small angle sothat the bearable load of the safety belt upon the seat occupant willpivot the seat as quickly as possibly into the relatively safe accidentposition. The energy-dissipating element may therefore in this case beprovided, for example, in the form of at least one pin which, when theload of the safety belt reaches the still bearable limit, will be shomoff, for example, by one of the pivoting front legs. In order to preventthe seat from being tilted over toward the rear beyond the accidentposition, it is advisable to provide a suitable stop member. in additionto such a shearing pin, it is also possible to provide the lower ends ofthe front legs of the seat with friction brakes.

if such a seat is to be employed in a vehicle in which the seat shouldalso be tilted forwardly by hand, for example, in order to permit apassenger of a two-door sedan to enter the vehicle behind the tiltedfront seat so as to be able to sit down on a rear seat, theenergy-dissipating pin and the stop member may be designed so as topermit them to be moved, for example, by hand, to an inactive position.in order to permit the seat then to be pivoted forwardly and downwardly,it is advisable to design the guide means for the rear legs so thattheir front end curves upwardly as far as possible. This has the resultthat the back rest will then be pivoted very far forwardly anddownwardly.

The energy-dissipating elements according to the invention may be ofmany different designs. Since after a sudden strong deceleration of thevehicle the seat occupant must be prevented from again being propelledtoward the rear, the energy-dissipating elements should be preferably ofa type so as actually to dissipate energy and not merely to convert itin a manner which may again be reversed. Elements which reversallyconvert the energy may be employed, however, if suitable locking meansare provided which are capable of storing the absorbed energy for acertain length of time or of retarding its transmission for aconsiderable length of time. Such elements which may be truly regardedas energy-dissipating devices may be, for example, of the type whichconvert the absorbed energy by friction into heat or employ this energyin order to deform a suitable part permanently by cold-deformation. Itis, however, also possible to employ shock absorbers of a conventionaltype, provided special means are provided for insuring that such shockabsorbers will not become effective until the load upon the back restreaches the predetermined maximum limit. This may be effected, forexample, by providing an element which may be subjected to tension,bending or shearing and which at first takes up the load from the backrest and does not permit the shock absorber to be acted upon until ithas been broken or destroyed when the predetermined maximum load hasbeen reached.

For reasons of manufacture and attaining a most practical design, it isusually advisable to secure the back rest pivotably to the seat part,especially also because it is then possible to adjust the inclination ofthe back rest in a simple manner relative to the seat part. However, theback rest may also be connected to the seat part by means of an elasticintermediate element which is suitable, for example, also for so-calledbucket seats, or to provide suitable guide means, for example, in theform of an adjustable parallelogram, which permit the back rest to beshifted in the longitudinal direction of the seat.

The energy-dissipating element may be connected to or combined into astructural unit with a back-rest adjusting device and/or with a hingefitting which connects the back rest to the seat part. This may beattained by a simple construction, for example, in a manner as disclosedby prior patents of the applicants or their assignees in regard to hingefittings for motor vehicle seats, in which the hinge fitting is designedso as to act as a friction brake.

in order to make the seat of the lowest possible weight and to requirethe lowest possible amount of material for producing its supportingparts, it is advisable to employ a construction in which the stresseswhich are exerted by the safety belt upon the seat only result incompressive or tensile stresses but not in bending stresses upon partsof the seat frame. This may be attained by providing the back restand/or the seat part at least at the lateral side to which the safetybelt is secured with a framework, hereafter called a truss, theindividual bars or rods of which define a plane which extends parallelto the longitudinal plane of the seat within which the back rest ispivotable or is inclined thereto at no more than an acute angle. If theback rest is to be pivotable forwardly and at least some of the trussjoints of the truss of the back rest are provided in the form of hinges,the rear rod of such a truss will be subjected to tension and the frontrod to compression. If such a truss is employed for supporting a seat,the upper rods of this truss will then accordingly be subjected tocompression and the lower rod to tension when the back rest is supportedon these upper rods. Trusses of this kind which extend at both sidesforwardly on the back rest and upwardly on the seat part may, forexample, be embedded in lateral bulges of the seat and back rest so asnot to be noticeable. The trusses may, of course, also be designed sothat at least a part of its rods or bars are also subjected to bendingstresses. This would apply, for example, if the truss of the back restdoes not extend up to the upper end of the latter but if the safety beltis secured to this upper end. Generally speaking, however, it is moreadvisable to design the seat according to the invention in a manner soas to avoid bending stresses.

When supporting the seat and/or back rest by means of such trusses andat least some of the truss joints are provided in the form of hinges,the energy-dissipating element may be inserted into the connectionbetween two adjacent truss joints or form such a connection. It isusually of minor importance between which adjacent truss joints theenergy-dissipating element is inserted provided that this element, if ithas to take up compressive stresses, is inserted between two trussjoints which when subjected to such stresses tend to move toward eachother or, that if it has to take up tensile stresses, it is insertedbetween two truss joints which when subjected to such stresses tend tomove away from each other.

When employing one or more trusses in which at least some of the trussjoints are provided in the form of hinges, it is also very easilypossible to effect an adjustment of the inclination of the back rest. Itis then only necesary to provide one rod of a truss with a device foradjusting it to different lengths and for locking it in the adjustedposition. Such a back-rest adjusting device may connect, for example, afixed bearing of the seat with a movable bearing which is slidable inthe longitu dinal direction of the seat. This adjusting device may thenbe located underneath the seat and thus in a position in which it is notdirectly noticeable. lf according to a preferred embodiment of theinvention the trusses are designed so that their rods or bars form anadjustable parallelogram which connects the back rest to the seat part,two diametrically opposite truss joints of this parallelogram may beconnected to each other by a structural unit which consists of anenergy-dissipating element which is combined with a back-rest adjustingdevice, and also permits the height of the seat from the floor to beadjusted.

When employing, for example, triangular trusses on the seat part so thatat least one upper pair of truss joints is provided in the form ofhinges on the opposite lateral sides of the seat part, and if the heightof these two hinge points changes substantially equally when theinclination of the back rest is being adjusted, for example, by makingone of the rods of each truss of an adjustable length, it is also veryeasily possible to adjust the seat part to different heights from thefloor. It is then only necessary to suspend a seat-cushion support onthese upper hinge parts. If the rod of an adjustable length serves as aback-rest adjusting device, a pivoting movement of the back rest towardthe rear will at the same time result in a reduction of the height ofthe seat, while a forward pivoting movement of the back rest will causethe seat to be lowered.

The features and advantages of the following invention will becomefurther apparent from the following detailed description thereof whichis to be read with reference to the accompanying diagrammatic drawings,in which:

FIG. 1 shows a side view of the supporting structure of a seat accordingto a first embodiment of the invention, in which the outlines of thecushion surfaces are indicated in dot-and-dash lines;

FIG. 2 shows an enlarged longitudinal section of the energy-dissipatingelement according to the invention as employed in the seat structureaccording to F IG. 1;

FIG. 3 shows a side view similar to FIG. 1 of another embodiment of theinvention;

FIG. 4 shows a side view similar to FIG. I ofa modification of the seatsupporting structure according to FIG. 3 in which the seat part isadjustable to different heights;

FIG. 5 shows a cross section of the adjustable foot bracket as shown inFIG. 3;

FIG. 6 shows a side view similar to HQ 1 of another embodiment of theinvention with a back rest which is adjustable in the longitudinaldirection of the seat;

HO. 7 shows a side view similar to FIG. 1 ofa modification of thestructure according to FIG. 6;

FIG. 8 shows a very diagrammatic side view of another embodiment of theinvention;

HO. 9 shows a side view similar to FIG. 8 of a further embodiment of theinvention;

FIG. 10 shows a side view of a modification of the embodiment as shownin FIG. 9 with the seat in its normal sitting position;

FIG. 11 shows a side view of the seat according to FIG. 10in theaccident position;

FIG. [2 shows a side view of the seat according to FIG. 10 in theentering position;

FIG. 13 shows a diagrammatic side view of a further embodiment of theinvention;

H0. 14 shows a side view of the seat according to F 1G. 13 in theaccident position; while FIG. 15 shows a side view of the seat accordingto FIG. 13 in the entering position.

Referring first particularly to FIG. 1 of the drawings, the seat for acar or other motor vehicle comprises separate tubular frames forsupporting the cushion 3 of the back rest 1 and the cushion 4 of theseat part 2. Both frames are connected to each other at their oppositesides by means of two hinge fittings 5 of which only one is shown. Thesetwo hinge fittings are supported by rear foot brackets 6 which arerigidly secured to a fixed base 7, for example, to the floor of the car.The tubular frame of the seat part 2 is supported in front by two footbrackets 8 which are likewise rigidly secured to the floor 7 of the car.

Each of the two longitudinal rods or bars 9 of the frame of the seatpart 2, only one of which is shown, forms one arm of a triangular truss.The two frame parts at the two lateral sides of the seat aresubstantially identical so that only the one which is shown in FIG. 1needs to be described.

The front end of the longitudinal bar 9 is rigidly secured to a bar 10which extends obliquely upward and to the rear. and the rear end of bar9 is secured to bar l l which extends obliquely upward and toward thefront. The other ends of the two bars l0 and 11 of the triangular trussare connected to each other by a truss joint [2. As may be seen in FIG.I, the shorter bar 11 is made of such a length relative to the longerbar 10 that the truss joint l2 will be located slightly above the seatcushion 4 and slightly in front of the back cushion 3. The plane whichis defined by this triangular truss extends parallel to the plane withinwhich the back rest 1 is pivotable and which extends at a right angle toits pivot axis. Truss 9 to 12 may therefore be easily embedded within alateral bulge 13 which projects for a maximum distance from the seatcushion adjacent to the hips of the seat occupant and graduallydecreases in distance from the back cushion toward the upper edge of theback rest 1. Of course, the other side of the seat which is not shownmay be provided with a similar lateral bulge.

The two frame bars 14 at both lateral sides of the back rest whichextend in the longitudinal direction thereof likewise form parts of twoequal triangular trusses which are embedded within the lateral forwardlyprojecting bulges 13.

The upper end of bar 14 is connected by a hinge fitting l5 to one end ofa bar 16 the other end of which is pivotably connected to the trussjoint 12. Bars l4, l6 and ll which together form this truss define aplane which likewise extends parallel to the plane within which the backrest 1 is pivoted.

Bar 16 is interrupted by a device for adjusting the inclination of theback rest and also by an energy-absorbing or dissipating element 18. Inthe embodiment of the invention as illustrated in FIG. 1, these twodevices are combined into one structural unit. By tuming a hand wheel 19in one direction the effective length of bar 16, i. e. the distancebetween its opposite ends, may be reduced and the back rest will therebybe pivoted forwardly, while by turning this hand wheel 19 in the otherdirection, the effective length of bar 16 will be increased and the backrest will be pivoted more toward the rear. Suitable locking means, notshown, may be provided for preventing the adjusted length of bar 16 frombeing changed unintentionally.

It is the purpose of the energy-dissipating element 18 to permit thetotal length of bar 16 to be changed if it is subjected to cornpresiveor tensile stresses beyond certain predetermined limits. At such achange in length of bar 16, the energy-dissipating element 18 is furtherdesigned to absorb energy and to dissipate or convert the same in anirreversable manner. In the embodiment of the invention as illustratedin FIGS. 1 and 2, this object is attained by providing this element 18in the form of a casing 20 which is connected to the part of bar 16which is pivotably connected to the truss joint 12, and by mounting twobushings 21 and 22 of different inner diameters at a certain axialdistance from each other in this casing 20. These two bushings areconnected to casing 20 so as not to be movable in their axial direction.These two bushings are separated by the thicker head 23' of a rod 23which is rigidly connected to the part of bar 16 which leads to thehinge fitting 15. The shank of rod 23 is longitudinally slidable inbushing 22. While the diameter of the bores in both bushings 21 and 22is smaller than the diameter of the head 23, the bore in bushing 21 isof a smaller diameter than the bore in bushing 22.

The safety belt (not shown) with which the seat occupant is strappedupon his seat is to be secured at one end to the hinge fitting 15 and atthe other end to the hinge fitting S at the other side of the seat whichcannot be seen in FIG. 1, or, if it is a three point safety belt, it isalso to be secured on the hinge fitting 5 which may be seen in FIG. 1.If a sudden strong deceleration of the vehicle occurs, for example, by ahead-on collision, the forwardly propelling body of the seat occupantstraining against the safety belt will tend to move the upper end of theback rest 1 forwardly and will thereby exert compressive stresses uponbar 16. The diameter of the bore in bushing 21 is therefore made of sucha size that the head 23' will not be forced through bushing 21 until theload which is exerted by the safety belt upon the body of the seatoccupant just reaches the highest value which is bearable withoutcausing any injuries. The energy of the thrust which is taken up by theelement 18 during the pivoting movement of back rest 1 toward the frontwhich is caused by the movement of the shank 23 relative to bushing 21will be spent for the cold deformation of bushing 21. The head 23' maypenetrate only to the lower end of bushing 2i which limits the angle towhich the back rest 1 may be pivoted.

Since even at a sudden high acceleration of a car in which the seatsaccording to the invention are mounted, as it may occur, for example, bythe impact upon its rear end by another car, it is of advantage to takeup at least a part of the energy of the impact by an energy-absorbing ordissipating element, the bore in bushing 22 is made of such a diameterthat the head 23 can be drawn through it only by deforming the bushing22. Numerous experiences and practical tests have shown that veryadvantageous results may be attained if the energy-absorbing ordissipating element 1.8 of the embodiment of the invention asillustrated in FIG. 1 is designed so that the force which is requiredfor the lastmentioned purpose is approximately 5 times as small as theforce which is required for forcing the head 23' through the bushing 21.

Since the force which is transmitted by the safety belt acts at theupper end of the back rest only upon the side where the hinge fitting islocated, it is usually only necessary to provide such an element 18 inthe bars 16 of the triangular trusses at both sides of the back rest.

In the embodiment of the invention as illustrated in FIG. 3, all thoseparts which are similar to the parts of the embodiment according to FIG.1 are designated by reference numbers which are increased by 100 overthose as used in FIG. I. The truss joint 112 between the adjacent endsof bars 110 and 111 is in this case provided in the form of a hingefitting since the device 117 for adjusting the back rest is not providedin bar 116 but in bar 109. This also requires one of the two pairs offoot brackets in this case the front bracket 108- to be adjustablyconnected to the fixed base 107, for example, to the floor of the car,in a manner so as to be movable in the longitudinal direction of theseat.

The back-rest adjusting device 117 comprises a tubular internallythreaded casing 124 which is rigidly secured to the part of bar 109which is connected to the hinge fitting 105, and a screw spindle 125which is rotatably connected to the part of bar 109 leading to the frontfoot bracket I08 and is adapted to be screwed to different depths intothe casing 124 by means of a hand crank 126 which is located underneaththe front end of the seat cushion 104. When the total length of bar 109is changed by means of the back-rest adjusting device 117, trussjointI12 pivots about the hinge fitting I05 at a radius which is equal to thelength ofbar l I 1.

The energy-dissipating element 118 is interposed between two sections ofbar 116 in the same manner as the element 18 in FIG. 1, although it may,of course, also be provided at another position of the truss asindicated in dotted lines in FIG. 3 by the element 118' between twosections of bar 114.

FIG. 5 illustrates that for preventing the front foot brackets 108 frombeing lifted off the base 107, they are slidable in guides I27 and 128which are only open at the sides facing each other and are located inthe door sill I29 and in the drive-shaft tunnel 130, respectively.

The further embodiment of the invention as illustrated in FIG. 4 differsfrom that according to FIG. 3 only by the addition of a cushion support109' which supports the seat cushion I04 and is suspended on thepivotable truss joints 112' at both sides of the seat. Since thedistance between the joint 112' and the base I07 increases when the backrest 101' is pivoted toward the rear and decreases when the back rest ispivoted forwardly, such a change in the inclination of the back restwill also result in an adjustment of the height ofthc seat from the baseor floor 107'.

FIG. 6 illustrates an embodiment of the invention in which the back rest201 is adjustable relative to the seat part 202 in the longitudinaldirection of the latter. For this purpose, a truss is provided on eachof both sides of the back rest and extends within a longitudinal planeof the seat and is embedded ina lateral bulge 213 of the seat. Sincethese two trusses are of the same shape and construction, only one ofthem will hereafter be described.

The rear end of a longitudinal bar 209 of the seat frame which carriesthe seat part 202 and is rigidly supported by the rear and front footbrackets 206 and 208 carries the lower end of a bar 232 which ispivotably connected thereto and extends in the longitudinal direction ofthe back rest 201 and slightly in front of the rear surface of the backrest. This bar 232 leads from the truss joint 233, which forms the pointof connection to the longitudinal bar 209, to a truss joint 234 whichlikewise forms a hinge and is located approximately at the level of thehips of the seat occupant. A bar 235 of the same length as bar 232 ispivotably connected to the longitudinal bar 209 by a truss joint 236which is spaced from the truss joint 233. The upper end of bar 235 isconnected to a truss joint 237 which forms a hinge fitting and isconnected to the truss joint 234 by a bar 238 which has a length equalto that of the section of the longitudinal bar 209 which connects thetwo truss joints 233 and 236. This section and bars 232, 235 and 238therefore form an adjustable parallelogram.

Adjacent to the upper end.of back rest 201 another truss joint 239 isprovided which is connected by a bar 240 to the truss joint 237 and by asecond bar 241 to the truss joint 234. A shell, not shown, which carriesthe cushion of the back rest is connected at its upper end to the trussjoint 239 and at its lower end to the truss joint 237.

A bar 242 extends from the truss joint 233 diagonally through theparallelogram to the truss joint 237. This bar 242 is divided into twosections between which an energy-absorbing or dissipating element 218 ismounted which is combined with a back-rest adjusting device of whichonly the hand wheel 219 is shown which when turned varies the totallength of bar 242 including the element 218. Depending upon whether bar242 is lengthened or shortened, the truss joint 237 together with backrest 201 is shifted forwardly or toward the rear, while the inclinationof the back rest remains unchanged.

The energy-dissipating element 218 permits the bar 242 to be extendedonly if in an accident the tension of a safety belt (not shown) which issecured to the back rest 241 increases to the bearable limit.

In order to permit the back rest 201 also to be adjusted to differentinclinations, bar 241 is provided with an adjusting device 243 by meansof which the total length of this bar may be varied. Such a change inthe length of bar 241 causes the back rest 201 to be pivoted about thehorizontal axis of the truss joint 237.

In addition to the back-rest adjusting device, bar 241 may also beprovided with an energy-dissipating device similar to that which isinserted between the sections of bar 242. If in an accident the tensionof the safety belt reaches the bearable limit, the back rest 201 wouldthen carry out a combined pivoting and translatory movement since inaddition to the longitudinal dis placement by the changing position ofthe parallelogram there would also occur the pivoting movement of theback rest about the axis of the truss joint 237.

FIG. 7 illustrates a modification of the embodiment of the invention asshown in FIG. 6 which differs from the latter merely by the fact thateach hingelike truss joint also forms a friction brake which permits theshape of the parallelogram to be changed only when the above-mentionedbearable tension of the safety belt is reached. These friction brakesthen take over the function of the energy-dissipating element 218 whichmay therefore be omitted. Of course, the number of friction brakes inthis structure may also be altered and be provided in a differentarrangement relative to the truss oints.

FIG. 8 illustrates diagrammatically a vehicle seat which comprises aseat part 301 whichis supported on a seat frame 302 on which a back rest303 is mounted in a conventional manner, for example, by being rigidlyconnected to the seat part 301 or by being adjustable to differentinclinations relative to the seat part by means of a back-rest adjustingdevice. At its front and rear ends, the two lateral sides of the seatframe 302 are pivotably connected to the upper ends of two pairs of legs304 and 305 of equal lengths the lower ends of which are pivotablyconnected at corresponding distances from each other to the floor 306.All of the pivot axes of legs 304 and 305 extend horizontally andtransverse to the longitudinal direction of the seat, and legs 304 and305, together with the seat frame 302 and the floor 306 therefore formtwo equal parallelograms.

The upper hinge point of each front leg 304 is connected by a rod 307 tothe lower hinge point of the associated rear leg 305. Rod 307 forms twosections between which an energy-dissipating element 308 is insertedwhich permits the effective total length of rod 307 to increase and atthe same time the energy which is necessary for such an extension to bematerially absorbed when in an accident an excessive tension is exertedupon rod 307. The energy-dissipating element 308 forms a unit togetherwith a device 309 for manually adjusting the normal length of rod 307,i. e. the distance between the hinged outer ends of its two sections.

In this embodiment of the invention as illustrated in FIG. 8, rod 307 ismade of such a length that in the normal sitting position of the seatoccupant the legs 304 and 305 are slightly forwardly inclined from thefloor 306. If a sudden deceleration of the vehicle occurs which exceedsa certain limit, a safety belt (not shown) with which the seat occupantis strapped upon his seat and one end of which is secured to the backrest 303 will transmit such a force upon the seat that theenergydissipating element 308 will permit the effective length of rod307 to be increased. The seat part 301 including the back rest 303 willthereby move forwardly and downwardly. At the same time the element 308absorbs and dissipates some of the energy which is produced by theforward movement of the seat and its occupant. By manually adjusting theeffective length of rod 307 by means of the adjusting device 309, it isalso possible to change the angle of inclination of legs 304 and 305relative to the floor 306 and thereby to vary the nonnal height of theseat part 301 from the floor.

FIG. 9 illustrates a modification of the seat supprting structure asshown in FIG. 8 which has the same advantage as the latter, namely, thatin the case of an accident the back rest 313 is capable of being movedfor a considerable distance against the action of the energydissipatingelement 318. The back rest 313 is connected to the seat part 311 in thesame manner as in the embodiment according to FIG. 8. However, the seatpart 311 is in this case supported on a seat frame 312 the rear end ofwhich is bent downwardly to form rear rigid legs 315 at both lateralsides of the seat. The lower end of each of these two legs 315 isslidably mounted in an upwardly and forwardly inclined slot 320 in abracket or the like which is rigidly secured to the floor 316.

The front end of the seat frame 312 is pivotably connected to a pair oflegs 314 which like the front legs 304 in FIG. 8 are pivotably connectedat their lower ends to the floor 316. The pivot axes at both ends oflegs 314 extend horizontally and transverse to the longitudinaldirection of the seat. The lower pivot axis of the front legs 314 isconnected to the lower ends of the rear legs 315 by at least one rod 317which together with the energy-dissipating element 318 and alengthadjusting device 319 forms a structural unit. The mode ofoperation of the adjusting device 319 is the same as that of the device309 as described with reference to FIG. 8. The energy-dissipatingelement 318, however, operates in the reverse manner to the element 308in FIG. 8, insofar as it effects a reduction of the effective length ofrod 317 when a compressive force which exceeds a certain strength isexerted upon its opposite ends. While the effective length of rod 317 isthus being reduced which results in a forward tilting movement of theseat, such an amount of energy will be absorbed by the element 318 thatat a sudden high deceleration of the car, for example, due to a head-oncollision, the safety belt (not shown) which is secured to the seat willusually not exert such a pressure upon the seat occupant that the lattermight thereby be injured.

In the embodiment of the invention as illustrated in FIGS. 10 to 12, thetwo front legs 324 of the seat which comprises a seat part 321 and aback rest 323 are designed in the same manner as the corresponding legsin F108 8 and 9 and are pivotably connected at their upper ends to theseat frame 322 and at their lower ends to the floor 326. The upper endsof the two rear legs 325 are rigidly secured to the seat frame 322similarly as shown in FIG. 9, while each of their lower ends slidablyengages into a forwardly and upwardly inclined guide slot 330 in abracket or the like which is secured to the floor 326.

The seat frame 322 is further provided on each lateral side with a leg331 which is rigidly secured thereto and extends approximately from thecenter of its length at an oblique angle downwardly and toward the rearto the lower end of the rear leg 325. Each of these inclined legs 331 isprovided with a longitudinal slot 332 into which one end of a rod 327engages the other end of which is pivotably connected to the floor 326so as to be pivotable, for example, about the pivot axis of the lowerend of the front leg 324. Rod 327 is again divided into two sectionsbetween which an energy-dissipating element 328 is inserted which, whenan excessive pressure of a certain strength is exerted upon the oppositeends of rod 327, shortens the total length of this rod and at the sametime absorbs energy. This element 328 forms a structural unit togetherwith a device for manually adjusting the normal length of rod 327including the unit 328 and for thereby varying the height of the seatfrom the floor.

The end of rod 327 which engages into the longitudinal slot 332 isadapted to be manually locked in its upper and position by means of ahook 333. If this hook 333 is pivoted upwardly by hand, it releases theend of rod 327 which engages into the longitudinal slot 332 so that thisend may slide to the other end of slot 332 as illustrated in FIG. 12.The seat may in this manner be shifted and tilted forwardly so as topermit a passenger, for example, of a two-door sedan, to enter the careasily behind the back rest 323 of the front seat so as to sit down onone of the rear seats.

If a sudden high deceleration of the vehicle occurs which exceeds apredetermined limit, the seat occupant who is strapped to the seat by asafety belt (not shown) pulls the seat by means of this safety beltforwardly with such a strength that rod 327 will be compressed and theenergy-dissipating element 328 will become effective and reduce thelength of rod 327, for example, to the position as illustrated in FIG.11. Of course, the upper end of rod 327 which engages into thelongitudinal slot 332 will at this time remain locked in its upper endposition by the hook 333.

The further embodiment of the invention as illustrated in FIGS. 13 to 15is likewise provided at both sides of the seat with a pair of front legs344 the upper ends of which are pivotably connected to the seat frame342 carrying the seat part 341, while their lower ends are pivotablyconnected to the floor 346. The pivot axes of legs 344 again extendhorizontally and transverse to the longitudinal direction of the seat.The upper ends of legs 344 are, however, pivotably connected at suchpositions to the seat frame 342 that, when the seat is in its normalposition as shown in FIG. 13, the front legs 344 extend at an obliqueangle forwardly and downwardly from the seat. The rear end of the seatframe 342 is provided with two rigid downwardly projecting legs 345. Thelower end of each of these legs 345 is guided in a slot 350 in a bracketor the like which is secured to the floor 346. From its rear end, thisslot 350 is at first downwardly inclined until near its front end itcurves upwardly.

In order to hold the seat in its normal position as shown in FIG. 13,each side of the seat frame 342 is provided with a stop projection 354,while from the bracket or the like which is secured to the floor and onwhich the lower end of the front leg 344 is pivotably mounted a shearingpin 355 projects which normally prevents the front leg 344 from pivotingforwardly. This shearing pin 355 which serves as an energy-dissipatingelement extends parallel to the pivot axis of leg 344 and is adapted tobe moved manually in its axial direction from its active position inwhich it engages with the leg 344 to a retracted position in which leg344 may pass over it,

If the vehicle in which this seat is mounted is suddenly deceleratedbeyond a predetermined limit, the tension which is exerted by the bodyof the seat occupant upon the safety belt with which he is strapped onthis seat will be so strong that pin 355 will be shorn off by the leg344. This shearing pin may be made ofsuch a material and such athickness that by being shom off by the leg 344 the desired amount ofthe energy will be consumed which is produced by the propulsion of theseat occupant and the movement of the seat. When pin 355 has been shornoff, leg 344 may pivot upwardly about its lower end and thereby permitthe seat to move to the accident position as shown in FIG. 14, in whichthe front edge of the seat part 341 is moved upwardly and its rear edgeand the lower edge of the back rest 343 are moved downwardly andforwardly so that the entire seat is tilted considerably toward therear. In this position of the seat, its occupant will be pressed by hisinertia primarily against the seat part 341. The safety belt which issecured to the seat itself and is preferably elastic may not beabsolutely required in this embodiment of the invention since theinertia which is exerted by the upper body of the seat occupant is atleast taken up to a considerable extent by the tilting movement of theseat.

When the seat has thus been shifted to the accident position as shown inFIG. 14, it will be stopped since each of the front legs 344 will thenabut against a stop member 356. This stop member 356 is preferablyconnected to the shearing pin 355 and likewise movable in its axialdirection so that both together may be moved manually from theirpositions in which they project into the path of travel of the front leg344 to their retracted positions in which this leg may be pivotedforwardly without engaging with either of these abutments. The emptyseat may then be shifted forwardly from its normal position as shown inFIG. 13 and past the accident position according to FIG. 14 to theentering position as shown in FIG. 15, in which the lower end of eachrear leg 34S abuts against the front end of the upwardly curving part ofthe associated guide slot 350 and the seat including its back rest isshifted and tilted so far forwardly that a passenger, for example, of atwo-door sedan, may easily enter the car behind this seat so as to sitdown on a rear seat.

Ofcourse, in addition to the shearing pins 355 additionalenergy-absorbing or dissipating means may be provided, for example, inthe form of a friction brake on one or both pivoting points of eachfront leg 344.

Although our invention has been illustrated and described with referenceto the preferred embodiments thereof, we wish to have it understood thatit is in no way limited to the details of such embodiments but iscapable of numerous modifications within the scope of the appendedclaims.

Having thus fully disclosed our invention, what we claim is:

l. A seat for a motor vehicle having a seat part and a back restpivotally connected to said seat part near the rear end of the latter soas to be pivotable about an axis extending substantially horizontallyand transversely to the longitudinal direction of said seat part, a seatoccupant being adapted to be strapped by a safety belt which is securedto the seat and at least one end of which is secured to the back rest, atruss means supporting said seat part and being mounted on said base,said truss means comprising a plurality of rods and joints connectingthe adjacent rods to each other and being disposed in a plane extendingsubstantially normal to said base and combination energy-dissipatingmeans and back rest adjusting means for manually adjusting the normalangle ofinclination of said back rest relative to said seat part, saidcombination energy-dissipating and back rest adjusting means beinginterposed in at least one of said rods of said truss means and beingconnected to said seat part.

2. A seat as defined in claim 1, in which said truss means comprise onefirst truss on at least one lateral side of said back rest and a secondtruss on the same side of said seat part and connected to said firsttruss.

3. A seat as defined in claim 1. in which said rods of said truss meansare connected to each other by joints so as to fomi a triangle.

4. A seat as defined in claim 2, in which the rods of each of said firstand second trusses are connected to each other by joints so as to form atriangle, two adjacent rods of said seat-part truss projecting upwardly,one of said two rods being common with and also forming one of the rodsof said back-rest truss, and the joints on the ends of said common rodconnecting the same to the two other rods of each of said trusses.

5. A seat as defined in claim 4, in which at least two of said joints ofsaid two trusses form hinges pivotably connecting the rods adjacent tosaid hinges so as to be pivotable relative to each other within theplane of said truss means.

6. A seat as defined in claim 1, in which said combinationenergy-dissipating and back rest adjusting means comprise at least twoelements, one of said elements being movable relative to the otherelement so as to act thereon in a manner so as permanently to deform thesame when said pressure of said safety belt upon the body of said seatoccupant reaches substantially said bearable limit.

7. A seat as defined in claim 1, in which said combinationenergy-dissipating means and back rest adjusting means are adapted toconsume energy when sub- |5 jected to compressive stresses and also whensubjected to tensile stresses.

* i t t

1. A seat for a motor vehicle having a seat part and a back restpivotally connected to said seat part near the rear end of the latter soas to be pivotable about an axis extending substantially horizontallyand transversely to the longitudinal direction of said seat part, a seatoccupant being adapted to be strapped by a safety belt which is securedto the seat and at least one end of which is secured to the back rest, atruss means supporting said seat part and being mounted on said base,said truss means comprising a plurality of rods and joints connectingthe adjacent rods to each other and being disposed in a plane extendingsubstantially normal to said base and combination energy-dissipatingmeans and back rest adjusting means for manually adjusting the normalangle of inclination of said back rest relative to said seat part, saidcombination energydissipating and back rest adjusting means beinginterposed in at least one of said rods of said truss means and beingconnected to said seat part.
 2. A seat as defined in claim 1, in whichsaid truss means comprise one first truss on at least one lateral sideof said back rest and a second truss on the same side of said seat partand connected to said first truss.
 3. A seat as defined in claim 1, inwhich said rods of said truss means are connected to each other byjoints so as to form a triangle.
 4. A seat as defined in claim 2, inwhich the rods of each of said first and second trusses are connected toeach other by joints so as to form a triangle, two adjacent rods of saidseat-part truss projecting upwardly, one of said two rods being commonwith and also forming one of the rods of said back-rest truss, and thejoints on the ends of said common rod connecting the same to the twoother rods of each of said trusses.
 5. A seat as defined in claim 4, inwhich at least two of said joints of said two trusses form hingespivotably connecting the rods adjacent to said hinges so as to bepivotable relative to each other within the plane of said truss means.6. A seat as defined in claim 1, in which said combinationenergy-dissipating and back rest adjusting means comprise at least twoelements, one of said elements being movable relative to the otherelement so as to act thereon in a manner so as permanently to deform thesame when said pressure of said safety belt upon the body of said seatoccupant reaches substantially said bearable limit.
 7. A seat as definedin claim 1, in which said combination energy-dissipating means and backrest adjusting means are adapted to consume energy when subjected tocompressive stresses and also when subjected to tensile stresses.